#include <stdlib.h>
#include <stdio.h>

#include "defs.h"

action **parser;
int SRtotal;
int RRtotal;
short *SRconflicts;
short *RRconflicts;
short *defred;
short *rules_used;
short nunused;
short final_state;

static int SRcount;
static int RRcount;

extern action *parse_actions(int stateno);
extern action *get_shifts(int stateno);
extern action *add_reductions(int stateno, action *actions);
extern action *add_reduce(action *actions, int ruleno, int symbol);

action *parse_actions(int stateno)
{
	action *actions;

	actions = get_shifts(stateno);
	actions = add_reductions(stateno, actions);
	return (actions);
}


action *get_shifts(int stateno)
{
	action *actions, *temp;
	shifts *sp;
	short *to_state;
	int i, k;
	int symbol;

	actions = 0;
	sp = shift_table[stateno];
	if (sp)
	{
		to_state = sp->shift;
		for (i = sp->nshifts - 1; i >= 0; i--)
		{
			k = to_state[i];
			symbol = accessing_symbol[k];
			if (ISTOKEN(symbol))
			{
				temp = NEW(action);
				temp->next = actions;
				temp->symbol = symbol;
				temp->number = k;
				temp->prec = symbol_prec[symbol];
				temp->action_code = SHIFT;
				temp->assoc = symbol_assoc[symbol];
				actions = temp;
			}
		}
	}
	return (actions);
}

action *add_reductions(int stateno, action *actions)
{
	int i, j, m, n;
	int ruleno, tokensetsize;
	unsigned int *rowp;

	tokensetsize = WORDSIZE(ntokens);
	m = lookaheads[stateno];
	n = lookaheads[stateno + 1];
	for (i = m; i < n; i++)
	{
		ruleno = LAruleno[i];
		rowp = LA + i * tokensetsize;
		for (j = ntokens - 1; j >= 0; j--)
		{
			if (BIT(rowp, j))
				actions = add_reduce(actions, ruleno, j);
		}
	}
	return (actions);
}


action *add_reduce(action *actions, int ruleno, int symbol)
{
	action *temp, *prev, *next;

	prev = 0;
	for (next = actions; next && next->symbol < symbol; next = next->next)
		prev = next;

	while (next && next->symbol == symbol && next->action_code == SHIFT)
	{
		prev = next;
		next = next->next;
	}

	while (next && next->symbol == symbol && next->action_code == REDUCE && next->number < ruleno)
	{
		prev = next;
		next = next->next;
	}

	temp = NEW(action);
	temp->next = next;
	temp->symbol = symbol;
	temp->number = ruleno;
	temp->prec = rprec[ruleno];
	temp->action_code = REDUCE;
	temp->assoc = rassoc[ruleno];

	if (prev)
		prev->next = temp;
	else
		actions = temp;

	return (actions);
}

void find_final_state(void)
{
	int goal, i;
	short *to_state;
	shifts *p;

	p = shift_table[0];
	to_state = p->shift;
	goal = ritem[1];
	for (i = p->nshifts - 1; i >= 0; --i)
	{
		final_state = to_state[i];
		if (accessing_symbol[final_state] == goal)
			break;
	}
}

void unused_rules(void)
{
	int i;
	action *p;

	rules_used = (short *) MALLOC(nrules * sizeof(short));
	if (rules_used == 0)
		no_space();

	for (i = 0; i < nrules; ++i)
		rules_used[i] = 0;

	for (i = 0; i < nstates; ++i)
	{
		for (p = parser[i]; p; p = p->next)
		{
			if (p->action_code == REDUCE && p->suppressed == 0)
				rules_used[p->number] = 1;
		}
	}

	nunused = 0;
	for (i = 3; i < nrules; ++i)
		if (!rules_used[i])
			++nunused;

	if (nunused)
		if (nunused == 1)
			fprintf(stderr, "%s: 1 rule never reduced\n", myname);
		else
			fprintf(stderr, "%s: %d rules never reduced\n", myname, nunused);
}

void remove_conflicts(void)
{
	int i;
	int symbol;
	action *p, *pref;

	SRtotal = 0;
	RRtotal = 0;
	SRconflicts = NEW2(nstates, short);
	RRconflicts = NEW2(nstates, short);
	for (i = 0; i < nstates; i++)
	{
		SRcount = 0;
		RRcount = 0;
		symbol = -1;
		for (p = parser[i]; p; p = p->next)
		{
			if (p->symbol != symbol)
			{
				pref = p;
				symbol = p->symbol;
			} else if (i == final_state && symbol == 0)
			{
				SRcount++;
				p->suppressed = 1;
			} else if (pref->action_code == SHIFT)
			{
				if (pref->prec > 0 && p->prec > 0)
				{
					if (pref->prec < p->prec)
					{
						pref->suppressed = 2;
						pref = p;
					} else if (pref->prec > p->prec)
					{
						p->suppressed = 2;
					} else if (pref->assoc == LEFT)
					{
						pref->suppressed = 2;
						pref = p;
					} else if (pref->assoc == RIGHT)
					{
						p->suppressed = 2;
					} else
					{
						pref->suppressed = 2;
						p->suppressed = 2;
					}
				} else
				{
					SRcount++;
					p->suppressed = 1;
				}
			} else
			{
				RRcount++;
				p->suppressed = 1;
			}
		}
		SRtotal += SRcount;
		RRtotal += RRcount;
		SRconflicts[i] = SRcount;
		RRconflicts[i] = RRcount;
	}
}

void total_conflicts(void)
{
	fprintf(stderr, "%s: ", myname);
	if (SRtotal == 1)
		fprintf(stderr, "1 shift/reduce conflict");
	else if (SRtotal > 1)
		fprintf(stderr, "%d shift/reduce conflicts", SRtotal);

	if (SRtotal && RRtotal)
		fprintf(stderr, ", ");

	if (RRtotal == 1)
		fprintf(stderr, "1 reduce/reduce conflict");
	else if (RRtotal > 1)
		fprintf(stderr, "%d reduce/reduce conflicts", RRtotal);

	fprintf(stderr, ".\n");
}


int sole_reduction(int stateno)
{
	int count, ruleno;
	action *p;

	count = 0;
	ruleno = 0;
	for (p = parser[stateno]; p; p = p->next)
	{
		if (p->action_code == SHIFT && p->suppressed == 0)
			return (0);
		else if (p->action_code == REDUCE && p->suppressed == 0)
		{
			if (ruleno > 0 && p->number != ruleno)
				return (0);
			if (p->symbol != 1)
				++count;
			ruleno = p->number;
		}
	}

	if (count == 0)
		return (0);
	return (ruleno);
}

void defreds(void)
{
	int i;

	defred = NEW2(nstates, short);
	for (i = 0; i < nstates; i++)
		defred[i] = sole_reduction(i);
}

void free_action_row(action *p)
{
	action *q;

	while (p)
	{
		q = p->next;
		FREE(p);
		p = q;
	}
}

void free_parser(void)
{
	int i;

	for (i = 0; i < nstates; i++)
		free_action_row(parser[i]);

	FREE(parser);
}

void make_parser(void)
{
	int i;

	parser = NEW2(nstates, action *);
	for (i = 0; i < nstates; i++)
		parser[i] = parse_actions(i);

	find_final_state();
	remove_conflicts();
	unused_rules();
	if (SRtotal + RRtotal > 0)
		total_conflicts();
	defreds();
}
